JP5348601B2 - Light source device, optical scanning device, and image forming apparatus - Google Patents

Abstract

A light source driver mounted on a rectangular-shaped substrate includes a plurality of output parts that output driving signals to drive a plurality of light-emitting bodies. The plurality of output parts are disposed in a vicinity of the two sides of the substrate, the two sides of the substrate forming a corner of the substrate.

Description

The present invention relates to an optical source apparatus, relates to an optical scanning device and an image forming apparatus, more particularly to a light source device that have a light source driver to output the drive signals of a plurality of light emitters, the optical scanning device having a light source device And an image forming apparatus including the optical scanning device.

  In electrophotographic image recording, an image forming apparatus using a laser is widely used. In this case, the image forming apparatus includes an optical scanning device, and forms a latent image by rotating the drum while scanning laser light using a polygon scanner (for example, a polygon mirror) in the axial direction of the photosensitive drum. Is common. In the field of electrophotography, an image forming apparatus is required to increase image density in order to improve image quality and to increase image output speed in order to improve operability.

  A method of simultaneously scanning a plurality of adjacent lines using a plurality of beams has been proposed.

  For example, in Patent Document 1, light emitting elements having a first electrode and a second electrode are two-dimensionally arranged in a long region, and are formed in a long side direction to which the first electrode is connected. An image forming apparatus having a light emitting element array in which first wirings as row wirings and second wirings as column wirings formed in a short side direction connected to the second electrode are connected in a matrix. Has been. In this light emitting element array, the two-dimensionally arranged light emitting element array is divided into a plurality of blocks that can be independently driven, and row wirings and column wirings are provided for the light emitting element arrays in each of the divided blocks. The lead lines of the row wiring are drawn out in the column direction.

  Patent Document 2 discloses a plurality of light emitting elements arranged on a base substrate and a plurality of electrodes individually connected by a plurality of wirings provided on the base substrate between the plurality of light emitting elements. A light emitting element array including a pad is disclosed. In this light emitting element array, the stray capacitances of the plurality of wirings are made substantially the same.

  Incidentally, in recent years, surface-emitting laser elements have attracted attention as light sources for image forming apparatuses.

  For example, Patent Document 3 discloses a first electrode for injecting a current into an active layer, which includes a multiple quantum well structure between an active layer and a pair of distributed Bragg reflectors facing each other with the active layer interposed therebetween. And a second electrode for applying an electric field to the multi-quantum well structure portion are provided independently, and the refractive index of the multi-quantum well structure portion is obtained by applying an electric field to the multi-quantum well structure portion by the second electrode. A surface emitting laser element is disclosed in which the oscillation wavelength is variable by changing the above. In this surface emitting laser element, GaInNAs mixed crystal is used as the material of the well layer of the multiple quantum well structure.

No. 2000-012973 No. 2002-314191 2002-217488

  In recent years, an image forming apparatus has been used for simple printing as an on-demand printing system, and accordingly, an image forming apparatus having a low price and excellent image quality is required.

A first object of the present invention is to provide a light source device capable of making the rising characteristics when a plurality of light emitters emit light equal to each other without increasing the cost.

A second object of the present invention is to provide an optical scanning device that can perform high-precision optical scanning without incurring high costs.

A third object of the present invention is to provide an image forming apparatus capable of forming a high quality image at high speed without incurring an increase in cost.

The present invention is, to a first aspect, a plurality of input drive signal of the multiple light emitters and the plurality of light emitters is inputted, a light source and mounted in the square shape of the first substrate; square a light source driver that is mounted on the second substrate shape; wherein the light source driver is located on one of the near corner of the second substrate, the one corner portion side of the second substrate A clock generation circuit for generating a reference clock for driving signals of a plurality of light emitters positioned, and one of the two sides forming the one corner, and is disposed in the vicinity of the plurality of light emitters. A first drive circuit that generates a part of the drive signals; a second drive circuit that is disposed in the vicinity of the other of the two sides and generates a drive signal for the remaining part of the plurality of light emitters; Arranged in the vicinity of one side to output drive signals for some of the light emitters A plurality of first output section that is disposed in the vicinity of the other side, has a plurality of second output section for outputting a drive signal of the remainder of the plurality of light emitters, the first substrate, The plurality of first output units of the light source driver are arranged so as to be approximately divided into two by a virtual straight line extending a diagonal line passing through one corner of the second substrate. It is on one side of a straight line and is connected to a plurality of input units on one side of the virtual straight line among the plurality of input units, and the plurality of second output units of the light source driver are connected to the virtual straight line. And a light source device connected to a plurality of input units on the other side of the virtual straight line among the plurality of input units .

According to this, it is possible to equalize the rising characteristics when a plurality of light emitters emit light without increasing the cost.

According to a second aspect of the present invention, there is provided an optical scanning device that scans a surface to be scanned with light, the light source device of the present invention; a deflector that deflects light from the light source device; and the deflector. A scanning optical system that condenses the deflected light on the surface to be scanned.

  According to this, since the light source device of the present invention is provided, as a result, high-accuracy optical scanning can be performed without increasing the cost.

According to a third aspect of the present invention, there is provided at least one image carrier; and at least one optical scanning device according to the invention that scans the at least one image carrier with light including image information. An image forming apparatus provided.

  According to this, since at least one optical scanning device of the present invention is provided, as a result, it is possible to form a high-quality image at a high speed without causing an increase in cost.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a laser printer 1000 as an image forming apparatus according to an embodiment of the present invention.

  The laser printer 1000 includes an optical scanning device 1010, a photosensitive drum 1030, a charging charger 1031, a developing roller 1032, a transfer charger 1033, a static elimination unit 1034, a cleaning blade 1035, a toner cartridge 1036, a paper supply roller 1037, a paper supply tray 1038, A registration roller pair 1039, a fixing roller 1041, a paper discharge roller 1042, a paper discharge tray 1043, and the like are provided.

  A photosensitive layer is formed on the surface of the photosensitive drum 1030. That is, the surface of the photoconductor drum 1030 is a scanned surface. Here, the photosensitive drum 1030 rotates in the direction of the arrow in FIG.

  The charging charger 1031, the developing roller 1032, the transfer charger 1033, the charge removal unit 1034, and the cleaning blade 1035 are each arranged in the vicinity of the surface of the photosensitive drum 1030. Then, with respect to the rotation direction of the photosensitive drum 1030, the charging charger 1031 → the developing roller 1032 → the transfer charger 1033 → the charge eliminating unit 1034 → the cleaning blade 1035 are arranged in this order.

  The charging charger 1031 uniformly charges the surface of the photosensitive drum 1030.

  The optical scanning device 1010 irradiates the surface of the photosensitive drum 1030 charged by the charging charger 1031 with light modulated based on image information from a host device (for example, a personal computer). As a result, a latent image corresponding to the image information is formed on the surface of the photosensitive drum 1030 on the surface of the photosensitive drum 1030. The latent image formed here moves in the direction of the developing roller 1032 as the photosensitive drum 1030 rotates. The configuration of the optical scanning device 1010 will be described later.

  The toner cartridge 1036 stores toner, and the toner is supplied to the developing roller 1032.

  The developing roller 1032 causes the toner supplied from the toner cartridge 1036 to adhere to the latent image formed on the surface of the photosensitive drum 1030 to visualize the image information. Here, the latent image to which the toner is attached (hereinafter also referred to as “toner image” for convenience) moves in the direction of the transfer charger 1033 as the photosensitive drum 1030 rotates.

  Recording paper 1040 is stored in the paper feed tray 1038. A paper feed roller 1037 is disposed in the vicinity of the paper feed tray 1038, and the paper feed roller 1037 takes out the recording paper 1040 one by one from the paper feed tray 1038 and conveys it to the registration roller pair 1039. The registration roller pair 1039 is disposed in the vicinity of the transfer roller 911, temporarily holds the recording paper 1040 taken out by the paper feeding roller 1037, and the recording paper 1040 is synchronized with the rotation of the photosensitive drum 1030. It is sent out toward the gap between 1030 and the transfer charger 1033.

  A voltage having a polarity opposite to that of the toner is applied to the transfer charger 1033 in order to electrically attract the toner on the surface of the photosensitive drum 1030 to the recording paper 1040. With this voltage, the toner image on the surface of the photosensitive drum 1030 is transferred to the recording paper 1040. The recording sheet 1040 transferred here is sent to the fixing roller 1041.

  In the fixing roller 1041, heat and pressure are applied to the recording paper 1040, whereby the toner is fixed on the recording paper 1040. The recording paper 1040 fixed here is sent to the paper discharge tray 1043 via the paper discharge roller 1042 and is sequentially stacked on the paper discharge tray 1043.

  The neutralization unit 1034 neutralizes the surface of the photosensitive drum 1030.

  The cleaning blade 1035 removes toner (residual toner) remaining on the surface of the photosensitive drum 1030. The removed residual toner is used again. The surface of the photosensitive drum 1030 from which the residual toner has been removed returns to the position of the charging charger 1031 again.

  Next, the configuration of the optical scanning device 1010 will be described. In the present specification, the longitudinal direction of the photosensitive drum 1030 will be described as a Y-axis direction, and directions orthogonal to each other in a plane perpendicular to the Y-axis direction will be described as an X-axis direction and a Z-axis direction.

  As shown in FIG. 2 as an example, the optical scanning device 1010 includes a light source unit 14, an aperture plate 23, a cylindrical lens 17, a reflection mirror 18, a polygon mirror 13, a deflector side scanning lens 11a, and an image plane side scanning lens. 11b and the like.

  As shown in FIG. 3 as an example, the light source unit 14 includes a light source 14A, a control circuit 14B, a PCB (Printed Circuit Board) 14C, an aperture plate 14D, a coupling lens 14E, a condensing lens 14F, a reflecting mirror 14G, and a light receiving unit. It has the element 14H.

  As shown in FIG. 4 as an example, the light source 14A has a two-dimensional array of vertical cavity surface emitting semiconductor lasers (VCSEL) in which 32 light emitting portions are formed on one rectangular substrate. Yes.

  This two-dimensional array has an angle θ from a direction corresponding to the main scanning direction (hereinafter also referred to as “M direction” for convenience) to a direction corresponding to the sub scanning direction (hereinafter also referred to as “S direction” for convenience). There are four light emitting part rows in which eight light emitting parts are arranged at equal intervals along a direction inclined by a distance (hereinafter referred to as “T direction” for convenience). These four light emitting unit rows are arranged at equal intervals in the S direction. That is, the 32 light emitting units are two-dimensionally arranged along the T direction and the S direction, respectively. Here, for the sake of convenience, the first light emitting unit row, the second light emitting unit row, the third light emitting unit row, and the fourth light emitting unit row are referred to from the top to the bottom in FIG. In the present specification, the “light emitting portion interval” refers to the distance between the centers of two light emitting portions.

  Further, in order to specify each light emitting unit, for convenience, as shown in FIG. 5, the eight light emitting units constituting the first light emitting unit row are denoted by v1 to v8 from the upper left to the lower right in FIG. The eight light emitting units constituting the second light emitting unit row are v9 to v16, the eight light emitting units constituting the third light emitting unit row are v17 to v24, and the eight light emitting units constituting the fourth light emitting unit row. V25 to v32.

  The two-dimensional array is accommodated in a QFP (Quad Flat Package) type package as shown in FIG. 6A as an example. Terminals in01 to in32 in FIG. 6A correspond to the light emitting units v1 to v32, and are input terminals to which respective driving signals are input. Note that the two-dimensional array may be housed in a BGA (Ball Grid Array) type package as shown in FIG. 6B as an example. Hereinafter, for convenience, a package containing a two-dimensional array is also referred to as a “light source package”.

  Returning to FIG. 3, the aperture plate 14 </ b> D is provided to separate a part of the light emitted from the light source 14 </ b> A as monitor light. The aperture plate 14D has an aperture and a reflective surface, and is disposed on the optical path of light emitted from the light source 14 so as to be inclined with respect to a virtual plane perpendicular to the light traveling direction. Most of the light emitted from the light source 14 passes through the opening of the aperture plate 14D, and the light reflected by the reflective surface of the aperture plate 14D becomes the monitor light.

  The coupling lens 14E makes light that has passed through the opening of the opening plate 14D substantially parallel light. Accordingly, substantially parallel light is output from the light source unit 14.

  The light reflected by the reflecting surface of the aperture plate 14D is collected by the condenser lens 14F and received by the light receiving element 14H via the reflecting mirror 14G. The light receiving element 14H outputs a signal (photoelectric conversion signal) corresponding to the amount of received light. The output signal of the light receiving element 14H is used to monitor the amount of light emitted from the light source 14A, and the drive current of each light emitting unit is corrected based on the monitoring result.

  As shown in FIG. 7 as an example, the control circuit 14B includes an image processing circuit 400a, two drive circuits (400b, 400c), and a pixel clock generation circuit 400d.

  The pixel clock generation circuit 400d generates a pixel clock signal that is a reference clock for optical scanning.

  The image processing circuit 400a performs predetermined halftone processing or the like on the raster-developed image data, supplies data relating to the light emitting units v1 to v16 to the drive circuit 400b, and drives data relating to the light emitting units v17 to v32. Supply to circuit 400c.

  As shown in FIG. 8A, the drive circuit 400b includes a write control circuit 411b and an output circuit 413b.

  When the writing control circuit 411b detects the start of scanning based on the output signal of the synchronization sensor (not shown), the writing control circuit 411b superimposes the data from the image processing circuit 400a on the pixel clock signal from the pixel clock generation circuit 400d, and v1 to v16. Independent modulation data is generated for each light emitting unit.

  The output circuit 413b generates drive signals for the light emitting units v1 to v16 based on the modulation data from the write control circuit 411b and outputs the drive signals to the light source 14A.

  As shown in FIG. 8B, the drive circuit 400c includes a write control circuit 411c and an output circuit 413c.

  When the writing control circuit 411c detects the start of scanning based on an output signal of a synchronization sensor (not shown), the writing control circuit 411c superimposes the data from the image processing circuit 400a on the pixel clock signal from the pixel clock generation circuit 400d, and v17 to v32 Independent modulation data is generated for each light emitting unit.

  The output circuit 413c generates a drive signal for each light emitting unit of v17 to v32 based on the modulation data from the writing control circuit 411c, and outputs it to the light source 14A.

  As an example, as shown in FIG. 9, the image processing circuit 400a, the two drive circuits (400b, 400c), and the pixel clock generation circuit 400d are mounted on a rectangular substrate P400.

  Here, the image processing circuit 400a is disposed substantially at the center of the substrate P400, and the two drive circuits (400b, 400c) are also referred to as one corner (hereinafter referred to as “corner G” for convenience). ) In the vicinity of the two sides forming Further, the pixel clock generation circuit 400d is disposed in the vicinity of the corner portion G.

  The board P400 on which various circuits are mounted is accommodated in a QFP type package as shown in FIG. 10 as an example. The terminals out01 to out16 close to the drive circuit 400b correspond to the light emitting units v1 to v16 and are output terminals from which the respective drive signals are output. The terminals out17 to out32 close to the drive circuit 400c correspond to the light emitting units v17 to v32, and are output terminals from which the respective drive signals are output. That is, the terminals out01 to out16 are output units of the drive circuit 400b, and the terminals out17 to out32 are output units of the drive circuit 400c. Hereinafter, for convenience, a package in which the substrate P400 is accommodated is also referred to as an “IC package”.

  As an example, as shown in FIG. 11, the control circuit 14B and the light source 14A include a virtual straight line VL1 obtained by extending a diagonal line passing through the corner portion G of the substrate P400 and a virtual line obtained by extending one diagonal line of the light source 14A. The straight lines VL2 are arranged so as to substantially coincide with each other.

  The terminals out01 to out32 of the IC package and the terminals in01 to in32 of the light source package are electrically connected by wirings L01 to L32 (see FIG. 12). In FIG. 12, only a part of the wiring is shown. Moreover, the solid line part and the broken line part in the wiring of FIG. 12 are wirings that pass through different layers, and the circles indicate vias. The variation in length between the wirings is smaller than the conventional one.

  FIG. 13 shows a conventional example in which two drive circuits (400b, 400c) are arranged to face each other. In this case, as shown in FIG. 14, the length variation between the wirings is large.

  By the way, generally, the pins of the IC package and the light source package have a parasitic capacitance. Further, the wiring itself that electrically connects the IC package and the light source package also has a coupling capacitance depending on the wiring width, wiring pattern, and the like. Therefore, even when an ideal rectangular current (or voltage) is generated in the drive circuit, an RC circuit is configured by the capacitance and the resistance component of the light emitting unit. Therefore, the waveform of the light emission level current supplied to the light emitting part is dull for the time constant τ obtained by τ = R × C.

  The above time constant does not differ much between the pins of the IC package and the pins of the light source package, but the wiring length for connecting them on the substrate is not necessarily the same length due to restrictions on the substrate. Since there is no limitation, there is a high possibility that the coupling capacity differs for each light emitting unit.

  In addition, when a light source having a two-dimensional array of VCSELs is used as a light source having a plurality of light emitting units, for example, the resistance component may be different between the light emitting units due to the arrangement pattern of the plurality of light emitting units or device variations. .

  The value of the time constant varies depending on the resistance and capacitance, so that the rise characteristic of the light emission level current supplied to each light emitting unit varies, and this variation becomes the variation of the optical waveform, which is used in the optical scanning device. This leads to variations in the amount of scanning light. Also, when used in an image forming apparatus, it leads to uneven density of the image, making it difficult to form a high quality image.

Incidentally, FIG. 15 shows a comparison diagram of the time constant and the rise characteristic. For example, when it is desired to apply a certain constant current in a pulse shape, when the absolute value is 1, the time constant τ indicates the time when the magnitude of the current is (1−e ⁻¹ ). On the other hand, when the rising characteristic is calculated by the 10-90% method, the rising time ta indicates the time until the magnitude of the current changes from 0.1 to 0.9. When considering the response characteristics of a pulse waveform, it is easy to understand the rise characteristics. Therefore, when the relation between the rise characteristics and the time constant is obtained from the relational expression between them, the rise time ta = 2.2 × τ. . The same applies to the fall time.

  FIG. 16A schematically shows the waveform of the current (or voltage) generated in the light source driver, and FIG. 16B shows the waveform of the current supplied to the light emitting unit through the wiring. It is shown as an image. For example, when the length of the wiring L1 <the length of the wiring L2 <the length of the wiring L3, the capacitance of the IC pin, the capacitance of the light source pin, and the resistance component of the light emitting portion are hardly different between the light emitting portions. As for the waveform of the current supplied to the light emitting part through the wiring, the shortest wiring length has the best rise characteristic, and the longer the wiring length, the more blunt the waveform.

  In the present embodiment, since the variation in length between the wirings is small, the waveform of the current supplied to each light emitting unit is almost the same waveform.

  In the present embodiment, the light source 14A, the control circuit 14B, and the light receiving element 14H are mounted on the PCB 14C (see FIG. 3).

  Returning to FIG. 2, the aperture plate 23 has an aperture that defines the beam diameter of at least the Z-axis direction of the light that has passed through the coupling lens 15.

  The cylindrical lens 17 forms an image of the light that has passed through the opening of the aperture plate 23 in the vicinity of the deflection reflection surface of the polygon mirror 13 with respect to the Z-axis direction via the reflection mirror 18.

  Incidentally, the optical system arranged on the optical path between the light source 14A and the polygon mirror 13 is also called a pre-deflector optical system. In the present embodiment, the pre-deflector optical system includes a coupling lens 14E, an aperture plate 23, a cylindrical lens 17 and a reflection mirror 18.

  The polygon mirror 13 has a four-sided mirror, and each mirror serves as a deflection reflection surface. The polygon mirror 13 rotates at a constant speed around a rotation axis parallel to the Z-axis direction, and deflects light incident through the reflection mirror 18.

  The deflector-side scanning lens 11 a is disposed on the optical path of the light deflected by the polygon mirror 13.

  The image plane side scanning lens 11b is disposed on the optical path of light via the deflector side scanning lens 11a.

  The optical system arranged on the optical path between the polygon mirror 13 and the photosensitive drum 1030 is also called a scanning optical system. In the present embodiment, the scanning optical system includes a deflector side scanning lens 11a and an image plane side scanning lens 11b.

  The light deflected by the polygon mirror 13 is imaged by the scanning optical system and condensed as a light spot on the surface of the photosensitive drum 1030.

  Accordingly, as the polygon mirror 13 rotates, the light spot on the surface of the photosensitive drum 1030 moves in the Y-axis direction. The moving direction of the light spot at this time is the main scanning direction.

  As is clear from the above description, in the optical scanning device 100 according to the present embodiment, the light source driver is configured by the control circuit 14B.

  Further, the light source device is configured by the light source 14A, the control circuit 14B, and the wirings L01 to L32.

  As described above, according to the optical scanning device 100 according to the present embodiment, the light source unit 14 includes the light source 14A having a plurality of light emitting units and the control circuit 14B that controls the light source 14A, and the control circuit 14B. The output parts of the two drive circuits (400b, 400c) are arranged in the vicinity of the two sides forming the corner part G, respectively. Further, in the control circuit 14B and the light source 14A, the virtual straight line VL1 obtained by extending the diagonal line passing through the corner portion G of the substrate P400 and the virtual straight line VL2 obtained by extending one diagonal line of the light source 14A substantially coincide with each other. Has been placed. And the output part of the drive circuit in the same side with respect to a virtual straight line and the input part of the light source 14A are connected by the some wiring. Thereby, the variation in length can be reduced in the plurality of wirings that electrically connect the control circuit 14B and the light source 14A. Therefore, the rising characteristics of the light emitting units can be made substantially equal to each other, and as a result, high-precision optical scanning can be performed without increasing the cost.

  Further, according to the optical scanning device 100 according to the present embodiment, since the pixel clock generation circuit 400d is disposed in the vicinity of the corner portion G, the distance between each drive circuit and the pixel clock generation circuit 400d is shorter than the conventional one. Accordingly, it is possible to suppress the delay of the pixel clock signal.

  Further, according to the optical scanning device 100 according to the present embodiment, as shown in FIG. 17 as an example, it is not necessary to change the layout even if the image processing circuit 400a is enlarged.

  In addition, according to the optical scanning device 100 according to the present embodiment, the signal line between the image processing circuit 400a and each drive circuit and the signal line between the pixel clock generation circuit 400d and each drive circuit cross each other. Since the number of locations can be reduced, deterioration of the pixel clock signal can be suppressed.

  In addition, the laser printer 1000 according to the present embodiment includes the optical scanning device 1010 that can perform high-accuracy optical scanning without incurring an increase in cost. As a result, the cost increases without incurring an increase in cost. Quality images can be formed at high speed.

  In the above-described embodiment, as shown in FIG. 18 as an example, the control circuit 14B and the light source 14A are configured such that the virtual straight line VL1 extending the diagonal passing through the corner portion G of the substrate P400 and the light source 14A face each other. You may arrange | position so that the virtual straight line VL3 which extended one of the lines which connect the middle point of an edge | side may correspond substantially. Also in this case, the same effect as the above embodiment can be obtained.

  Moreover, although the said embodiment demonstrated the case where the board | substrate P400 in which various circuits were mounted is accommodated in the QFP type package, it is not limited to this. For example, as shown in FIG. 19A, it may be accommodated in a BGA type package. In this case, as shown in FIG. 19B, among the plurality of terminals, a plurality of terminals located at positions close to the drive circuits are used as output terminals for signals to the light source 14A. Similar effects can be obtained.

  In the above embodiment, the case where the light emitting unit is a VCSEL has been described. However, the present invention is not limited to this, and may be a red LD, for example. Since red LD has a large internal resistance, a particularly great effect is expected.

  Moreover, although the said embodiment demonstrated the case where 14 A of light sources have 32 light emission parts, it is not limited to this, What is necessary is just to have a some light emission part. The arrangement of the plurality of light emitting units may be one-dimensional.

  In the above embodiment, the laser printer 1000 is described as the image forming apparatus. However, the present invention is not limited to this. In short, an image forming apparatus including the optical scanning device 1010 can form a high-quality image at a high speed without increasing the cost.

  Further, the image forming apparatus may include the optical scanning device 1010 and directly irradiate a laser beam onto a medium (for example, paper) that develops color with laser light.

  Further, an image forming apparatus using a silver salt film as the image carrier may be used. In this case, a latent image is formed on the silver salt film by optical scanning, and this latent image can be visualized by a process equivalent to a developing process in a normal silver salt photographic process. Then, it can be transferred to photographic paper by a process equivalent to a printing process in a normal silver salt photographic process. Such an image forming apparatus can be implemented as an optical plate making apparatus or an optical drawing apparatus that draws a CT scan image or the like.

  As an example, as shown in FIG. 20, the image forming apparatus may be a tandem color machine corresponding to a color image and including a plurality of photosensitive drums. The tandem color machine includes a black (K) photosensitive drum K1, a charger K2, a developing device K4, a cleaning unit K5, a transfer charging unit K6, a cyan (C) photosensitive drum C1, and a charger. C2, developing unit C4, cleaning unit C5, transfer charging unit C6, magenta (M) photosensitive drum M1, charging unit M2, developing unit M4, cleaning unit M5, transfer charging unit M6, yellow (Y) photosensitive drum Y1, charging unit Y2, developing unit Y4, cleaning unit Y5, transfer charging unit Y6, optical scanning device 1010A, transfer belt 80, fixing unit 30 and the like.

  The optical scanning device 1010A includes a light emitting unit for black, a light emitting unit for cyan, a light emitting unit for magenta, and a light emitting unit for yellow.

  The light from the black light emitting unit is irradiated to the photosensitive drum K1 via the black scanning optical system, and the light from the cyan light emitting unit is irradiated to the photosensitive drum C1 through the cyan scanning optical system. The light from the light emitting unit for magenta is irradiated to the photosensitive drum M1 through the scanning optical system for magenta, and the light from the light emitting unit for yellow is irradiated to the photosensitive member through the scanning optical system for yellow. The drum Y1 is irradiated. Note that an optical scanning device 1010 may be provided for each color.

  Each photosensitive drum rotates in the direction of the arrow in FIG. 20, and a charger, a developer, a transfer charging unit, and a cleaning unit are arranged in the order of rotation. Each charger uniformly charges the surface of the corresponding photosensitive drum. The surface of the photosensitive drum charged by the charger is irradiated with light by the optical scanning device 1010A, and an electrostatic latent image is formed on the photosensitive drum. Then, a toner image is formed on the surface of the photosensitive drum by the corresponding developing device. Further, the toner images of the respective colors are transferred onto the recording paper by the corresponding transfer charging means, and finally the image is fixed on the recording paper by the fixing means 30.

As described above, according to the light source equipment of the present invention, without incurring high cost, it is suitable for equal rising characteristics of a plurality of light sources. Further, the optical scanning device of the present invention is suitable for performing high-accuracy optical scanning without incurring high costs. The image forming apparatus according to the present invention is suitable for forming a high-quality image at high speed without incurring an increase in cost.

It is a figure for demonstrating schematic structure of the laser printer which concerns on one Embodiment of this invention. It is a figure for demonstrating schematic structure of the optical scanning device in FIG. It is a figure for demonstrating the light source unit in FIG. It is a figure for demonstrating the arrangement | sequence of a some light emission part. It is a figure for demonstrating the light emission parts v1-v32. 6A and 6B are diagrams for explaining the light source package. It is a block diagram of the control circuit of a light source unit. 8A and 8B are diagrams for explaining the drive circuit in FIG. 7, respectively. It is a figure for demonstrating arrangement | positioning of each drive circuit. It is a figure for demonstrating the output terminal of the drive signal in IC package. It is a figure for demonstrating the positional relationship of an IC package and a light source package. It is a figure for demonstrating the wiring which connects an IC package and a light source package. It is a figure for demonstrating arrangement | positioning of each conventional drive circuit. It is a figure for demonstrating the example of the positional relationship of the conventional IC package and a light source package. It is a figure for demonstrating the relationship between a time constant and a starting characteristic. FIG. 16A is a waveform diagram of a current (or voltage) generated in the drive circuit, and FIG. 16B is a waveform diagram of a current supplied to the light emitting unit. It is a figure for demonstrating the increase in an image processing circuit. It is a figure for demonstrating the modification of the positional relationship of an IC package and a light source package. FIG. 19A is a diagram for explaining a modification of the IC package, and FIG. 19B is a diagram for explaining output terminals of drive signals in the IC package of FIG. 19A. It is a figure for demonstrating schematic structure of a tandem color machine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11a ... Deflector side scanning lens (a part of scanning optical system), 11b ... Image surface side scanning lens (a part of scanning optical system), 13 ... Polygon mirror (deflector), 14 ... Light source unit, 14A ... Light source, 14B ... Control circuit (light source driver), 1000 ... Laser printer (image forming device), 1010 ... Optical scanning device, 1010A ... Optical scanning device, 1030 ... Photosensitive drum (image carrier), K1, C1, M1, Y1 ... Photosensitive drum (image carrier), in01 to 32... Input terminal (input unit), out01 to 32... Output terminal (output unit), VL1.

Claims (8)

A light source in which a plurality of light emitters and a plurality of input portions to which drive signals of the plurality of light emitters are input are mounted on a rectangular first substrate;
A light source driver mounted on a square-shaped second substrate;
The light source driver is
A clock generation circuit that is disposed near one corner of the second substrate and generates a reference clock for driving signals of a plurality of light emitters located on the one corner of the second substrate;
A first drive circuit disposed in the vicinity of one of the two sides forming the one corner and generating a drive signal for a part of the plurality of light emitters;
A second drive circuit disposed in the vicinity of the other of the two sides and generating a drive signal for the remaining portions of the plurality of light emitters;
A plurality of first output units arranged in the vicinity of the one side and outputting a drive signal of a part of the plurality of light emitters;
A plurality of second output units that are disposed in the vicinity of the other side and that output drive signals of the remaining portions of the plurality of light emitters,
The first substrate is arranged so as to be divided into approximately two equal parts by a virtual straight line extending a diagonal line passing through one corner of the second substrate,
The plurality of first output units of the light source driver are on one side of the virtual straight line, and are connected to a plurality of input units on one side of the virtual straight line among the plurality of input units,
It said plurality of second output section of the source driver is located on the other side of the imaginary straight line, that is connected to a plurality of input portions on the other side of the imaginary straight line out of the plurality of input light source apparatus. The light source device according to claim 1, wherein the second substrate is accommodated in a QFP type package. The second substrate is accommodated in a BGA type package having a plurality of terminals,
Among the plurality of terminals, a plurality of terminals in the vicinity of the one side are the plurality of first output units, and among the plurality of terminals, a plurality of terminals in the vicinity of the other side are The light source device according to claim 1, wherein the light source device is the second output unit. The virtual straight line extending a diagonal line passing through one corner of the second substrate and the virtual straight line extending a diagonal line of the first substrate substantially coincide with each other. The light source device according to any one of 1 to 3 . A virtual straight line extending a diagonal line passing through one corner of the second substrate and a virtual straight line extending one of the lines connecting the midpoints of the two opposite sides of the first substrate are substantially one. The light source device according to claim 1, wherein the light source device is provided. An optical scanning device that scans a surface to be scanned with light,
A light source device according to any one of claims 1 to 5 ;
A deflector for deflecting light from the light source device;
A scanning optical system for condensing the light deflected by the deflector onto the surface to be scanned. At least one image carrier;
An image forming apparatus comprising: at least one optical scanning device according to claim 6 that scans light including image information on the at least one image carrier. The image forming apparatus according to claim 7 , wherein the image information is multicolor image information.

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